9. Make sure the all required traffic is allowed through access lists and/or firewalls. (Required traffic is UDP/500 and either ESP protocol or UDP/4500, depending on whether you're traversing a NAT device)

As long as you have the required info, it's pretty straightforward. One thing to keep in mind is that it is NOT forgiving of typos, or mis-matched settings. It will just fail.

This is a common question. and unfortunately I am not good enough with Cisco to help you. What I could suggest is you search through EE because I see this questions posted 2 - 3 times a day so there is most likely a great guide for you that has been in a previous question. Of course other experts will comment in time but in the meantime I would suggest you do some searching :) you might manage to find the answer you need before an expert can specifically explain the config of your exact setup.